An energy-efficient approach for information transfer from distributed wireless sensor systems

We present a method for reconfiguring the communication and computational burden between a system consisting of two subsystems: a wireless ground-based sensor network, and an overhead unmanned aerial vehicle (UAV). A small subset of sensor nodes receives and aggregates information gathered by the network, and forms a distributed antenna array, concentrating the radiated transmission into a narrow beam aimed towards the UAV. We describe and analyze two alternative strategies to bring the UAV and the sensor network´s beam into alignment, while minimizing the energy expended by the sensor network. The performance of the two strategies is compared in terms of probability of beam-UAV alignment as a function of time, and the expected time to alignment. We examine the performance tradeoff between the choice of strategy and parameters of the sensor network that affect power conservation